1. Field of the Invention
The present invention relates to a charge transfer amplifier circuit capable of highly precise amplification, to a voltage comparator, and to a sense amplifier.
2. Description of the Related Art
A/D converters, which are circuits which convert analog signals into digital signals, are extremely important circuits which are necessary as interfaces connecting the real world, in which all values comprise analog signals, with the computer world, in which digital values are employed. In particular, in recent years, data terminals have been reduced in size and become portable, and there have been strong demands for a reduction in the amount of power consumed by the A/D converters.
Standard A/D converters employ either a chopper type CMOS inverter or a differential amplifier as the comparator, and since a stationary direct electrical current (the auto zero current in the chopper and the bias current in the differential amplifier) flows in such devices, the power consumption increases.
In order to effect a reduction in power consumption, A/D converters have been developed which employ dynamic latch (sense amplifier) voltage comparator circuits (see FIG. 17), which do not involve stationary power consumption.
However, these dynamic latch circuits do not have mechanisms for canceling fluctuations in the element characteristics, such as the threshold value and the like, so that when used as comparators, variations in the offset voltage are produced, the comparison accuracy is poor, and such devices are not applicable as highly accurate A/D converters.